Test 2 Calculating standard potential #7


Moderators: Chem_Mod, Chem_Admin

Fenared Ortiz 3K
Posts: 37
Joined: Wed Nov 16, 2016 3:03 am

Test 2 Calculating standard potential #7

Postby Fenared Ortiz 3K » Tue Mar 13, 2018 7:41 pm

Calculate the standard potential for the following reactions using the standard reduction potential on the last page of the test:
Cr2O7 + 14H+ +12e- ---> 2Cr(s)+7H2O(l) Eo= 1.33V

How would we approach this problem? At first I thought that we had to find the standard Gibbs energy, but this was marked off on the test and I am curious on how to fully solve it

Nha Dang 2I
Posts: 53
Joined: Fri Sep 29, 2017 7:07 am

Re: Test 2 Calculating standard potential #7

Postby Nha Dang 2I » Tue Mar 13, 2018 7:47 pm

You're trying to find the standard potential for the whole reaction using the reduction potentials given.

You can set it up by saying detG(3)=detG(1)+detG(2) with 3 being the whole reaction, and 1 and 2 being the parts of the reaction with the reduction potential given.

You then plug in -nFE for each of detG, and then plug in the given numbers.

Hellen Truong 2J
Posts: 50
Joined: Sat Jul 22, 2017 3:00 am
Been upvoted: 1 time

Re: Test 2 Calculating standard potential #7

Postby Hellen Truong 2J » Fri Mar 16, 2018 3:01 am

I used this method! I got points on the calculations for deltaG(1) and (2), but then I am confused about the final calculation for the standard potential. I added the two values, then divided by -(12mol)*(96485C/mol). I got -0.01V. How can I correct this?


Return to “Work, Gibbs Free Energy, Cell (Redox) Potentials”

Who is online

Users browsing this forum: No registered users and 1 guest